Reverse engineering a mobile phone e-paper display

While e-paper is common among e-readers, there are very few, if any phones other than the MOTOFONE that exclusively use an e-paper display. [Steve] had one of these phones sitting around and thought it could be used to build a low-power clock. Since the bistable e-paper display can retain the currently active content even when power is removed, he would only need to update the clock once a minute, when the time changed.

Unfortunately for him, very little publicly-available documentation exists for the display controller Motorola used. To get an idea of how the display was driven, he had to sniff the SPI communications between the processor and the display. Once he had the basic commands down, he spent quite a bit of time figuring out how to activate the different segments of the display, due to what seems to be a rushed design process on Motorola’s part.

Now that [Steve] had reverse-engineered just about everything, he connected the phone to a TI MSP430 to drive the display. He programmed the LaunchPad to serve as a basic clock with great results, as you can see in the video below.

If your interest in e-paper hacking has been piqued, be sure to check out our previous e-paper coverage here.

honestly a great little phone. it’s my “camping” phone. not that i make calls while camping, but it has fantastic battery life and I don’t have to worry about it like i would with carrying in my smartphone for no reason. plus it was only about $40, so you really just don’t have to worry about it like the $500 beast i use daily.

This is great! I have one of those phones I bought in Brazil and haven’t been able to use in the U.S. I’ve always wanted to build an automatic story generator that outputs one sentence each time I start my car. Maybe this will be the platform for it.